The history of Poles in Windsor closely parallels that of Poles in Detroit in the United States, who settled there as early as 1854. The first Polish family was registered in Windsor in 1908. In 1914, around 300 Polish emigrants arrived here, coming mainly from the Austrian and Russian partitions. However, the numerous influx of Poles to this locality did not take place until after the Second World War. According to the 2001 Canadian census, approximately 11,000 people living in the Windsor area were of Polish origin.

Between 1915 and 1916, pastoral care for the Poles in Windsor was provided in English by Father Raphael Hubert Dignan, acting vicar at the English parish of the Immaculate Conception of the Blessed Virgin Mary. He celebrated masses for the Poles and the sermons preached in English were translated by one of the Polish emigrants. Pastoral ministry in Polish was started by Fr Jan Andrzejewski from the USA.

Fr Jan Andrzejewski arrived in Windsor on 29 September 1916, and just a few days later held the first service in the basement of the Immaculate Conception Church. When a large number of Poles had taken Confirmation, Father Bishop Michael Fallon appointed Father Andrzejewski as organiser and pastor of the Polish parish.

Unfortunately, when a fire broke out in the Church of the Immaculate Conception, the young Polish parish had to look for a new prayer shelter. True, it found a temporary place in St Anne's Church in Walkerville, but only for a short time, as the idea of building its own church was then born.

"It was decided to begin fund-raising by means of a monthly house collection and parishioners Joseph Samborski, Ignatius Leskiewicz and others were chosen as collectors," noted the Diary of the Fortieth Anniversary of Holy Trinity Parish in Windsor, Ontario 1916-1956 , Orchard Lake. "After their first visit to the parishioners they brought in $137.50. It is not difficult to calculate that with such monthly receipts the parish would have had to wait a long time for a church of its own. Despite such uninviting beginnings, 62 parishioners came to the second parish meeting and Franciszek Wandor, seconded by Andrzej Jakubiak, presented a motion to undertake the building of their own church. And the motion was passed with enthusiasm. A building committee was elected, consisting of Michał Winiarz, Ignacy Leśkiewicz, Michał Grycan, Franciszek Wandor, Antoni Kwapisz, Bazyli Jaworski, Andrzej Jakubiak, Józef Seń and Franciszek Pastuszak. In addition, a special tax of one dollar per month was passed for the purpose of construction. But the enthusiasm and generosity of the parishioners would not have advanced the cause very far had it not been for the help of God, so evidently always supporting good though weak human intentions. Fr Andrzejewski had a lot of courage, but he also had a great ability to win people over. Thanks to this ability, a great deal of help came from the unexpected. A non-Pole and Protestant, Mr Walter Boug, donated a plot of land at the intersection of Langlois and Banwell Streets (today's Ellis), the size of six normal building plots , for the construction of the church. However, he attached a condition to the donation: If the parish did not start building the church by 1 June 1918 and did not complete it within a year, he would withdraw the donation. It should be noted that the site, today located in the middle of the town of Windsor, was at that time an open field, as evidenced by surviving photographs showing parishioners digging pits for foundations and basements . Today's powerful digging machines did not exist and the parishioners did the arduous work by hand and hauled the earth away on horseback. Similarly, the parishioners also carried out the hauling of the material and other necessary building work themselves. This contribution of their own labour was necessary as they proceeded to start construction with two thousand dollars in cash. But it was also truly sacrificial, for as early as the 27th of October 1917, the Revd Bishop Fallon was able to arrive for the ceremonial consecration of the foundation stone."

The building work took five months and the first Mass was celebrated in the new church at Easter 1918. The consecration of Holy Trinity Church was carried out by Bishop M. Fallon in 1919. The 360-seat church has a parish hall with a stage in the basement. The organ for the church was donated by the parish of the Immaculate Conception of the Blessed Virgin Mary in 1918.

The rectory, which replaced a small building previously used for this purpose, was built in 1950.

For the 40th anniversary of the parish in 1956, the parish priest, Fr Ludwik Kociszewski, carried out work to rebuild and renovate the interior of the church and sacristy. A sculpture of the Holy Trinity was installed in the main altar. The arrangement of the three Divine Persons is reminiscent of the work of redemption. The sculpture was made in walnut wood by Jan Rylko. In turn, the interior of the great altar and the mosaic were created by the well-known Polish painter Karol Malczyk (see St Joseph's Church in Brantford).

On 12 December 1965, a convent of the Ursuline Sisters SJK was opened and dedicated at the parish.

On 22 October 2000, the 22nd anniversary of the election of Cardinal Karol Wojtyla as Pope, a statue of John Paul II was erected in front of the church. The unveiling act was performed by Bishop Sherlock in the presence of the Deputy Prime Minister of Canada Herb Grey and a representative of the Polish government, the Consul General of the Republic of Poland in Toronto Dr. Jacek Junoszy-Kisielewski and representatives of Polish community organisations in Windsor.

The monument was designed by Professor Władysław Dudek and executed in the studio of Stefan Kowalówka in Kraków.